(i) Technical Field
The present invention relates to a semiconductor laser.
(ii) Related Art
A sampled grating, in which segments including a diffraction grating region having a diffraction grating and a space region are combined, is known. The sampled grating has a wavelength selection function. Japanese Patent Application Publication No. 2008-277758 (hereinafter referred to as Document 1) discloses a semiconductor laser in which a SG-DFB (Sampled Grating Distributed Feedback) region having a SG (Sampled Grating) and a gain and a SG-DBR (Sampled Grating Distributed Bragg Reflector) region not having a gain and acting as a wavelength selection mirror are combined.